//
// Copyright (c) 2009-2011 Krueger Systems, Inc.
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//

#if WINDOWS_PHONE
#define USE_CSHARP_SQLITE
#endif

using System;
using System.Runtime.InteropServices;
using System.Collections.Generic;
using System.Reflection;
using System.Linq;
using System.Linq.Expressions;

#if USE_CSHARP_SQLITE
using Community.CsharpSqlite;
using Sqlite3DatabaseHandle = Community.CsharpSqlite.Sqlite3.sqlite3;
using Sqlite3Statement = Community.CsharpSqlite.Sqlite3.Vdbe;
#else
using Sqlite3DatabaseHandle = System.IntPtr;
using Sqlite3Statement = System.IntPtr;
#endif

namespace GlobalTracker.Mobile.SQLite
{
    public class SQLiteException : System.Exception {
        public SQLite3.Result Result { get; private set; }

        protected SQLiteException(SQLite3.Result r, string message)
            : base(message)
        {
            Result = r;
        }

        public static SQLiteException New(SQLite3.Result r, string message)
        {
            return new SQLiteException(r, message);
        }
    }

    /// <summary>
    /// Represents an open connection to a SQLite database.
    /// </summary>
    public class SQLiteConnection : IDisposable {
        private bool _open;
        private TimeSpan _busyTimeout;
        private Dictionary<string, TableMapping> _mappings = null;
        private Dictionary<string, TableMapping> _tables = null;
        private System.Diagnostics.Stopwatch _sw;
        private long _elapsedMilliseconds = 0;

        public Sqlite3DatabaseHandle Handle { get; private set; }
#if USE_CSHARP_SQLITE
        internal static readonly Sqlite3DatabaseHandle NullHandle = null;
#else
		internal static readonly Sqlite3DatabaseHandle NullHandle = IntPtr.Zero;
#endif

        public string DatabasePath { get; private set; }

        public bool TimeExecution { get; set; }

        public bool Trace { get; set; }

        /// <summary>
        /// Constructs a new SQLiteConnection and opens a SQLite database specified by databasePath.
        /// </summary>
        /// <param name="databasePath">
        /// Specifies the path to the database file.
        /// </param>
        public SQLiteConnection(string databasePath)
        {
            DatabasePath = databasePath;
            Sqlite3DatabaseHandle handle;
            var r = SQLite3.Open(DatabasePath, out handle);
            Handle = handle;
            if (r != SQLite3.Result.OK) {
                throw SQLiteException.New(r, "Could not open database file: " + DatabasePath);
            }
            _open = true;

            BusyTimeout = TimeSpan.FromSeconds(0.1);
        }

        static SQLiteConnection()
        {
            if (_preserveDuringLinkMagic) {
                var ti = new TableInfo();
                ti.name = "magic";
            }
        }

        /// <summary>
        /// Used to list some code that we want the MonoTouch linker
        /// to see, but that we never want to actually execute.
        /// </summary>
        static bool _preserveDuringLinkMagic = false;

        /// <summary>
        /// Sets a busy handler to sleep the specified amount of time when a table is locked.
        /// The handler will sleep multiple times until a total time of <see cref="BusyTimeout"/> has accumulated.
        /// </summary>
        public TimeSpan BusyTimeout
        {
            get { return _busyTimeout; }
            set
            {
                _busyTimeout = value;
                if (Handle != NullHandle) {
                    SQLite3.BusyTimeout(Handle, (int)_busyTimeout.TotalMilliseconds);
                }
            }
        }

        /// <summary>
        /// Returns the mappings from types to tables that the connection
        /// currently understands.
        /// </summary>
        public IEnumerable<TableMapping> TableMappings
        {
            get
            {
                if (_tables == null) {
                    return Enumerable.Empty<TableMapping>();
                } else {
                    return _tables.Values;
                }
            }
        }

        /// <summary>
        /// Retrieves the mapping that is automatically generated for the given type.
        /// </summary>
        /// <param name="type">
        /// The type whose mapping to the database is returned.
        /// </param>
        /// <returns>
        /// The mapping represents the schema of the columns of the database and contains 
        /// methods to set and get properties of objects.
        /// </returns>
        public TableMapping GetMapping(Type type)
        {
            if (_mappings == null) {
                _mappings = new Dictionary<string, TableMapping>();
            }
            TableMapping map;
            if (!_mappings.TryGetValue(type.FullName, out map)) {
                map = new TableMapping(type);
                _mappings[type.FullName] = map;
            }
            return map;
        }

        public void CriarTabelaConfiguracoes()
        {          
          var query = "create table if not exists \"Configuracao\"(\n" +
            "\"nome\" TEXT," +
            "\"email\" TEXT," +
            "\"webservice\" TEXT," +
            "\"intervalo\" INTEGER," +
            "\"senha\" TEXT" +
            ")";
          Execute(query);

          if (RetornaWebServiceConfiguracoes() == null)
            Execute("insert into Configuracao (webservice) values ('http://www.innovaresw.com.br/GlobalTracker/WebService/GeneralService.asmx')");
        }

        public string RetornaNomeConfiguracoes()
        {
          var command = this.CreateCommand("SELECT nome FROM Configuracao");
          string result = command.ExecuteScalar<string>();

          return result;
        }

        public string RetornaEMailConfiguracoes()
        {
          var command = this.CreateCommand("SELECT email FROM Configuracao");
          string result = command.ExecuteScalar<string>();

          return result;
        }

        public string RetornaIntervaloConfiguracoes()
        {
          var command = this.CreateCommand("SELECT intervalo FROM Configuracao");
          string result = command.ExecuteScalar<string>();

          return result;
        }

        public string RetornaSenhaConfiguracoes()
        {
          var command = this.CreateCommand("SELECT senha FROM Configuracao");
          string result = command.ExecuteScalar<string>();

          return result;
        }

        public string RetornaWebServiceConfiguracoes()
        {
          var command = this.CreateCommand("SELECT webservice FROM Configuracao");
          string result = command.ExecuteScalar<string>();

          return result;
        }

        public class TableInfo {
            public int cid { get; set; }

            public string name { get; set; }

            public string type { get; set; }

            public int notnull { get; set; }

            public string dflt_value { get; set; }

            public int pk { get; set; }
        }

        void MigrateTable(TableMapping map)
        {
            var query = "pragma table_info(\"" + map.TableName + "\")";

            var existingCols = Query<TableInfo>(query);

            var toBeAdded = new List<TableMapping.Column>();

            foreach (var p in map.Columns) {
                var found = false;
                foreach (var c in existingCols) {
                    found = p.Name == c.name;
                    if (found)
                        break;
                }
                if (!found) {
                    toBeAdded.Add(p);
                }
            }

            foreach (var p in toBeAdded) {
                var addCol = "alter table \"" + map.TableName + "\" add column " + Orm.SqlDecl(p);
                Execute(addCol);
            }
        }

        /// <summary>
        /// Creates a new SQLiteCommand given the command text with arguments. Place a '?'
        /// in the command text for each of the arguments.
        /// </summary>
        /// <param name="cmdText">
        /// The fully escaped SQL.
        /// </param>
        /// <param name="args">
        /// Arguments to substitute for the occurences of '?' in the command text.
        /// </param>
        /// <returns>
        /// A <see cref="SQLiteCommand"/>
        /// </returns>
        public SQLiteCommand CreateCommand(string cmdText, params object[] ps)
        {
            if (!_open) {
                throw SQLiteException.New(SQLite3.Result.Error, "Cannot create commands from unopened database");
            } else {
                var cmd = new SQLiteCommand(this);
                cmd.CommandText = cmdText;
                foreach (var o in ps) {
                    cmd.Bind(o);
                }
                return cmd;
            }
        }

        /// <summary>
        /// Creates a SQLiteCommand given the command text (SQL) with arguments. Place a '?'
        /// in the command text for each of the arguments and then executes that command.
        /// Use this method instead of Query when you don't expect rows back. Such cases include
        /// INSERTs, UPDATEs, and DELETEs.
        /// You can set the Trace or TimeExecution properties of the connection
        /// to profile execution.
        /// </summary>
        /// <param name="query">
        /// The fully escaped SQL.
        /// </param>
        /// <param name="args">
        /// Arguments to substitute for the occurences of '?' in the query.
        /// </param>
        /// <returns>
        /// The number of rows modified in the database as a result of this execution.
        /// </returns>
        public int Execute(string query, params object[] args)
        {
            var cmd = CreateCommand(query, args);

            if (TimeExecution) {
                if (_sw == null) {
                    _sw = new System.Diagnostics.Stopwatch();
                }
                _sw.Reset();
                _sw.Start();
            }

            int r = cmd.ExecuteNonQuery();

            if (TimeExecution) {
                _sw.Stop();
                _elapsedMilliseconds += _sw.ElapsedMilliseconds;
#if DEBUG
                Console.WriteLine("Finished in {0} ms ({1:0.0} s total)", _sw.ElapsedMilliseconds, _elapsedMilliseconds / 1000.0);
#endif
            }

            return r;
        }

        public bool ExisteTabela(string tabela)
        {
          var command = this.CreateCommand("SELECT name FROM sqlite_master WHERE type='table' AND name='" + tabela + "'");
          var result = command.ExecuteScalar<string>();                  

          if ((result != null) && (result.Trim().Length > 0))
            return true;
          else
            return false;
        }

        /// <summary>
        /// Creates a SQLiteCommand given the command text (SQL) with arguments. Place a '?'
        /// in the command text for each of the arguments and then executes that command.
        /// It returns each row of the result using the mapping automatically generated for
        /// the given type.
        /// </summary>
        /// <param name="query">
        /// The fully escaped SQL.
        /// </param>
        /// <param name="args">
        /// Arguments to substitute for the occurences of '?' in the query.
        /// </param>
        /// <returns>
        /// An enumerable with one result for each row returned by the query.
        /// </returns>
        public List<T> Query<T>(string query, params object[] args) where T : new()
        {
            var cmd = CreateCommand(query, args);
            return cmd.ExecuteQuery<T>();
        }

        /// <summary>
        /// Creates a SQLiteCommand given the command text (SQL) with arguments. Place a '?'
        /// in the command text for each of the arguments and then executes that command.
        /// It returns each row of the result using the mapping automatically generated for
        /// the given type.
        /// </summary>
        /// <param name="query">
        /// The fully escaped SQL.
        /// </param>
        /// <param name="args">
        /// Arguments to substitute for the occurences of '?' in the query.
        /// </param>
        /// <returns>
        /// An enumerable with one result for each row returned by the query.
        /// The enumerator will call sqlite3_step on each call to MoveNext, so the database
        /// connection must remain open for the lifetime of the enumerator.
        /// </returns>
        public IEnumerable<T> DeferredQuery<T>(string query, params object[] args) where T : new()
        {
            var cmd = CreateCommand(query, args);
            return cmd.ExecuteDeferredQuery<T>();
        }

        /// <summary>
        /// Creates a SQLiteCommand given the command text (SQL) with arguments. Place a '?'
        /// in the command text for each of the arguments and then executes that command.
        /// It returns each row of the result using the specified mapping. This function is
        /// only used by libraries in order to query the database via introspection. It is
        /// normally not used.
        /// </summary>
        /// <param name="map">
        /// A <see cref="TableMapping"/> to use to convert the resulting rows
        /// into objects.
        /// </param>
        /// <param name="query">
        /// The fully escaped SQL.
        /// </param>
        /// <param name="args">
        /// Arguments to substitute for the occurences of '?' in the query.
        /// </param>
        /// <returns>
        /// An enumerable with one result for each row returned by the query.
        /// </returns>
        public List<object> Query(TableMapping map, string query, params object[] args)
        {
            var cmd = CreateCommand(query, args);
            return cmd.ExecuteQuery<object>(map);
        }

        /// <summary>
        /// Creates a SQLiteCommand given the command text (SQL) with arguments. Place a '?'
        /// in the command text for each of the arguments and then executes that command.
        /// It returns each row of the result using the specified mapping. This function is
        /// only used by libraries in order to query the database via introspection. It is
        /// normally not used.
        /// </summary>
        /// <param name="map">
        /// A <see cref="TableMapping"/> to use to convert the resulting rows
        /// into objects.
        /// </param>
        /// <param name="query">
        /// The fully escaped SQL.
        /// </param>
        /// <param name="args">
        /// Arguments to substitute for the occurences of '?' in the query.
        /// </param>
        /// <returns>
        /// An enumerable with one result for each row returned by the query.
        /// The enumerator will call sqlite3_step on each call to MoveNext, so the database
        /// connection must remain open for the lifetime of the enumerator.
        /// </returns>
        public IEnumerable<object> DeferredQuery(TableMapping map, string query, params object[] args)
        {
            var cmd = CreateCommand(query, args);
            return cmd.ExecuteDeferredQuery<object>(map);
        }

        /// <summary>
        /// Returns a queryable interface to the table represented by the given type.
        /// </summary>
        /// <returns>
        /// A queryable object that is able to translate Where, OrderBy, and Take
        /// queries into native SQL.
        /// </returns>
        public TableQuery<T> Table<T>() where T : new()
        {
            return new TableQuery<T>(this);
        }

        /// <summary>
        /// Attempts to retrieve an object with the given primary key from the table
        /// associated with the specified type. Use of this method requires that
        /// the given type have a designated PrimaryKey (using the PrimaryKeyAttribute).
        /// </summary>
        /// <param name="pk">
        /// The primary key.
        /// </param>
        /// <returns>
        /// The object with the given primary key. Throws a not found exception
        /// if the object is not found.
        /// </returns>
        public T Get<T>(object pk) where T : new()
        {
            var map = GetMapping(typeof(T));
            string query = string.Format("select * from \"{0}\" where \"{1}\" = ?", map.TableName, map.PK.Name);
            return Query<T>(query, pk).First();
        }

        /// <summary>
        /// Whether <see cref="BeginTransaction"/> has been called and the database is waiting for a <see cref="Commit"/>.
        /// </summary>
        public bool IsInTransaction { get; private set; }

        /// <summary>
        /// Begins a new transaction. Call <see cref="Commit"/> to end the transaction.
        /// </summary>
        public void BeginTransaction()
        {
            if (!IsInTransaction) {
                Execute("begin transaction");
                IsInTransaction = true;
            }
        }

        /// <summary>
        /// Rolls back the transaction that was begun by <see cref="BeginTransaction"/>.
        /// </summary>
        public void Rollback()
        {
            if (IsInTransaction) {
                Execute("rollback");
                IsInTransaction = false;
            }
        }

        /// <summary>
        /// Commits the transaction that was begun by <see cref="BeginTransaction"/>.
        /// </summary>
        public void Commit()
        {
            if (IsInTransaction) {
                Execute("commit");
                IsInTransaction = false;
            }
        }

        /// <summary>
        /// Executes <param name="action"> within a transaction and automatically rollsback the transaction
        /// if an exception occurs. The exception is rethrown.
        /// </summary>
        /// <param name="action">
        /// The <see cref="Action"/> to perform within a transaction. <param name="action"> can contain any number
        /// of operations on the connection but should never call <see cref="BeginTransaction"/>,
        /// <see cref="Rollback"/>, or <see cref="Commit"/>.
        /// </param>
        public void RunInTransaction(Action action)
        {
            if (IsInTransaction) {
                throw new InvalidOperationException("The connection must not already be in a transaction when RunInTransaction is called");
            }
            try {
                BeginTransaction();
                action();
                Commit();
            } catch (Exception) {
                Rollback();
                throw;
            }
        }

        /// <summary>
        /// Inserts all specified objects.
        /// </summary>
        /// <param name="objects">
        /// An <see cref="IEnumerable"/> of the objects to insert.
        /// </param>
        /// <returns>
        /// The number of rows added to the table.
        /// </returns>
        public int InsertAll(System.Collections.IEnumerable objects)
        {
            BeginTransaction();
            var c = 0;
            foreach (var r in objects) {
                c += Insert(r);
            }
            Commit();
            return c;
        }

        /// <summary>
        /// Inserts the given object and retrieves its
        /// auto incremented primary key if it has one.
        /// </summary>
        /// <param name="obj">
        /// The object to insert.
        /// </param>
        /// <returns>
        /// The number of rows added to the table.
        /// </returns>
        public int Insert(object obj)
        {
            if (obj == null) {
                return 0;
            }
            return Insert(obj, "", obj.GetType());
        }

        public int Insert(object obj, Type objType)
        {
            return Insert(obj, "", objType);
        }

        public int Insert(object obj, string extra)
        {
            if (obj == null) {
                return 0;
            }
            return Insert(obj, extra, obj.GetType());
        }

        /// <summary>
        /// Inserts the given object and retrieves its
        /// auto incremented primary key if it has one.
        /// </summary>
        /// <param name="obj">
        /// The object to insert.
        /// </param>
        /// <param name="extra">
        /// Literal SQL code that gets placed into the command. INSERT {extra} INTO ...
        /// </param>
        /// <returns>
        /// The number of rows added to the table.
        /// </returns>
        public int Insert(object obj, string extra, Type objType)
        {
          if (obj == null || objType == null)
          {
            return 0;
          }

          var map = GetMapping(objType);

          var cols = map.InsertColumns;
          var vals = new object[cols.Length];
          for (var i = 0; i < vals.Length; i++)
          {
            vals[i] = cols[i].GetValue(obj);
          }

          var insertCmd = map.GetInsertCommand(this, extra);

          try
          {
            var count = insertCmd.ExecuteNonQuery(vals);

            if (map.HasAutoIncPK)
            {
              var id = SQLite3.LastInsertRowid(Handle);
              map.SetAutoIncPK(obj, id);
            }

            return count;
          }
          catch (System.Exception e)
          {
            return 0;
          }
        }

        /// <summary>
        /// Updates all of the columns of a table using the specified object
        /// except for its primary key.
        /// The object is required to have a primary key.
        /// </summary>
        /// <param name="obj">
        /// The object to update. It must have a primary key designated using the PrimaryKeyAttribute.
        /// </param>
        /// <returns>
        /// The number of rows updated.
        /// </returns>
        public int Update(object obj)
        {
            if (obj == null) {
                return 0;
            }
            return Update(obj, obj.GetType());
        }

        public int Update(object obj, Type objType)
        {
            if (obj == null || objType == null) {
                return 0;
            }

            var map = GetMapping(objType);

            var pk = map.PK;

            if (pk == null) {
                throw new NotSupportedException("Cannot update " + map.TableName + ": it has no PK");
            }

            var cols = from p in map.Columns
                       where p != pk
                       select p;
            var vals = from c in cols
                       select c.GetValue(obj);
            var ps = new List<object>(vals);
            ps.Add(pk.GetValue(obj));
            var q = string.Format("update \"{0}\" set {1} where {2} = ? ", map.TableName, string.Join(",", (from c in cols
                                                                                                            select "\"" + c.Name + "\" = ? ").ToArray()), pk.Name);
            return Execute(q, ps.ToArray());
        }

        /// <summary>
        /// Deletes the given object from the database using its primary key.
        /// </summary>
        /// <param name="obj">
        /// The object to delete. It must have a primary key designated using the PrimaryKeyAttribute.
        /// </param>
        /// <returns>
        /// The number of rows deleted.
        /// </returns>
        public int Delete<T>(T obj)
        {
            var map = GetMapping(obj.GetType());
            var pk = map.PK;
            if (pk == null) {
                throw new NotSupportedException("Cannot delete " + map.TableName + ": it has no PK");
            }
            var q = string.Format("delete from \"{0}\" where \"{1}\" = ?", map.TableName, pk.Name);
            return Execute(q, pk.GetValue(obj));
        }

        public void Dispose()
        {
            Close();
        }

        public void Close()
        {
            if (_open && Handle != NullHandle) {
                try {
                    foreach (var sqlInsertCommand in _mappings.Values) {
                        sqlInsertCommand.Dispose();
                    }
                    var r = SQLite3.Close(Handle);
                    if (r != SQLite3.Result.OK) {
                        string msg = SQLite3.GetErrmsg(Handle);
                        throw SQLiteException.New(r, msg);
                    }
                } finally {
                    Handle = NullHandle;
                    _open = false;
                }
            }
        }
    }

    public class PrimaryKeyAttribute : Attribute {
    }

    public class AutoIncrementAttribute : Attribute {
    }

    public class IndexedAttribute : Attribute {
    }

    public class IgnoreAttribute : Attribute {
    }

    public class MaxLengthAttribute : Attribute {
        public int Value { get; private set; }

        public MaxLengthAttribute(int length)
        {
            Value = length;
        }
    }

    public class CollationAttribute : Attribute {
        public string Value { get; private set; }

        public CollationAttribute(string collation)
        {
            Value = collation;
        }
    }

    public class TableMapping {
        public Type MappedType { get; private set; }

        public string TableName { get; private set; }

        public Column[] Columns { get; private set; }

        public Column PK { get; private set; }

        Column _autoPk = null;
        Column[] _insertColumns = null;

        public TableMapping(Type type)
        {
            MappedType = type;
            TableName = MappedType.Name;
            var props = MappedType.GetProperties(BindingFlags.Public | BindingFlags.Instance | BindingFlags.SetProperty);
            var cols = new List<Column>();
            foreach (var p in props) {
                var ignore = p.GetCustomAttributes(typeof(IgnoreAttribute), true).Length > 0;
                if (p.CanWrite && !ignore) {
                    cols.Add(new PropColumn(p));
                }
            }
            Columns = cols.ToArray();
            foreach (var c in Columns) {
                if (c.IsAutoInc && c.IsPK) {
                    _autoPk = c;
                }
                if (c.IsPK) {
                    PK = c;
                }
            }

            HasAutoIncPK = _autoPk != null;
        }

        public bool HasAutoIncPK { get; private set; }

        public void SetAutoIncPK(object obj, long id)
        {
            if (_autoPk != null) {
                _autoPk.SetValue(obj, Convert.ChangeType(id, _autoPk.ColumnType, null));
            }
        }

        public Column[] InsertColumns
        {
            get
            {
                if (_insertColumns == null) {
                    _insertColumns = Columns.Where(c => !c.IsAutoInc).ToArray();
                }
                return _insertColumns;
            }
        }

        public Column FindColumn(string name)
        {
            var exact = Columns.Where(c => c.Name == name).FirstOrDefault();
            return exact;
        }


        PreparedSqlLiteInsertCommand _insertCommand;
        string _insertCommandExtra = null;

        public PreparedSqlLiteInsertCommand GetInsertCommand(SQLiteConnection conn, string extra)
        {

            if (_insertCommand == null) {
                _insertCommand = CreateInsertCommand(conn, extra);
                _insertCommandExtra = extra;
            } else if (_insertCommandExtra != extra) {
                _insertCommand.Dispose();
                _insertCommand = CreateInsertCommand(conn, extra);
                _insertCommandExtra = extra;
            }
            return _insertCommand;
        }

        private PreparedSqlLiteInsertCommand CreateInsertCommand(SQLiteConnection conn, string extra)
        {
            var cols = InsertColumns;
            var insertSql = string.Format("insert {3} into \"{0}\"({1}) values ({2})", TableName,
                string.Join(",", (from c in cols
                                  select "\"" + c.Name + "\"").ToArray()),
                                   string.Join(",", (from c in cols
                                                     select "?").ToArray()), extra);

            var insertCommand = new PreparedSqlLiteInsertCommand(conn);
            insertCommand.CommandText = insertSql;
            return insertCommand;
        }

        protected internal void Dispose()
        {
            if (_insertCommand != null) {
                _insertCommand.Dispose();
                _insertCommand = null;
            }
        }

        public abstract class Column {
            public string Name { get; protected set; }

            public Type ColumnType { get; protected set; }

            public string Collation { get; protected set; }

            public bool IsAutoInc { get; protected set; }

            public bool IsPK { get; protected set; }

            public bool IsIndexed { get; protected set; }

            public bool IsNullable { get; protected set; }

            public int MaxStringLength { get; protected set; }

            public abstract void SetValue(object obj, object val);

            public abstract object GetValue(object obj);
        }

        public class PropColumn : Column {
            PropertyInfo _prop;

            public PropColumn(PropertyInfo prop)
            {
                _prop = prop;
                Name = prop.Name;
                //If this type is Nullable<T> then Nullable.GetUnderlyingType returns the T, otherwise it returns null, so get the the actual type instead
                ColumnType = Nullable.GetUnderlyingType(prop.PropertyType) ?? prop.PropertyType;
                Collation = Orm.Collation(prop);
                IsAutoInc = Orm.IsAutoInc(prop);
                IsPK = Orm.IsPK(prop);
                IsIndexed = Orm.IsIndexed(prop);
                IsNullable = !IsPK;
                MaxStringLength = Orm.MaxStringLength(prop);
            }

            public override void SetValue(object obj, object val)
            {
                _prop.SetValue(obj, val, null);
            }

            public override object GetValue(object obj)
            {
                return _prop.GetValue(obj, null);
            }
        }
    }

    public static class Orm {
        public const int DefaultMaxStringLength = 140;

        public static string SqlDecl(TableMapping.Column p)
        {
            string decl = "\"" + p.Name + "\" " + SqlType(p) + " ";

            if (p.IsPK) {
                decl += "primary key ";
            }
            if (p.IsAutoInc) {
                decl += "autoincrement ";
            }
            if (!p.IsNullable) {
                decl += "not null ";
            }
            if (!string.IsNullOrEmpty(p.Collation)) {
                decl += "collate " + p.Collation + " ";
            }

            return decl;
        }

        public static string SqlType(TableMapping.Column p)
        {
            var clrType = p.ColumnType;
            if (clrType == typeof(Boolean) || clrType == typeof(Byte) || clrType == typeof(UInt16) || clrType == typeof(SByte) || clrType == typeof(Int16) || clrType == typeof(Int32)) {
                return "integer";
            } else if (clrType == typeof(UInt32) || clrType == typeof(Int64)) {
                return "bigint";
            } else if (clrType == typeof(Single) || clrType == typeof(Double) || clrType == typeof(Decimal)) {
                return "float";
            } else if (clrType == typeof(String)) {
                int len = p.MaxStringLength;
                return "varchar(" + len + ")";
            } else if (clrType == typeof(DateTime)) {
                return "datetime";
            } else if (clrType.IsEnum) {
                return "integer";
            } else if (clrType == typeof(byte[])) {
                return "blob";
            } else {
                throw new NotSupportedException("Don't know about " + clrType);
            }
        }

        public static bool IsPK(MemberInfo p)
        {
            var attrs = p.GetCustomAttributes(typeof(PrimaryKeyAttribute), true);
            return attrs.Length > 0;
        }

        public static string Collation(MemberInfo p)
        {
            var attrs = p.GetCustomAttributes(typeof(CollationAttribute), true);
            if (attrs.Length > 0) {
                return ((CollationAttribute)attrs[0]).Value;
            } else {
                return string.Empty;
            }
        }

        public static bool IsAutoInc(MemberInfo p)
        {
            var attrs = p.GetCustomAttributes(typeof(AutoIncrementAttribute), true);
            return attrs.Length > 0;
        }

        public static bool IsIndexed(MemberInfo p)
        {
            var attrs = p.GetCustomAttributes(typeof(IndexedAttribute), true);
            return attrs.Length > 0;
        }

        public static int MaxStringLength(PropertyInfo p)
        {
            var attrs = p.GetCustomAttributes(typeof(MaxLengthAttribute), true);
            if (attrs.Length > 0) {
                return ((MaxLengthAttribute)attrs[0]).Value;
            } else {
                return DefaultMaxStringLength;
            }
        }
    }

    public class SQLiteCommand {
        SQLiteConnection _conn;
        private List<Binding> _bindings;

        public string CommandText { get; set; }

        internal SQLiteCommand(SQLiteConnection conn)
        {
            _conn = conn;
            _bindings = new List<Binding>();
            CommandText = "";
        }

        public int ExecuteNonQuery()
        {
            if (_conn.Trace) {
#if DEBUG
                Console.WriteLine("Executing: " + this);
#endif
            }

            var r = SQLite3.Result.OK;
            var stmt = Prepare();
            r = SQLite3.Step(stmt);
            Finalize(stmt);
            if (r == SQLite3.Result.Done) {
                int rowsAffected = SQLite3.Changes(_conn.Handle);
                return rowsAffected;
            } else if (r == SQLite3.Result.Error) {
                string msg = SQLite3.GetErrmsg(_conn.Handle);
                throw SQLiteException.New(r, msg);
            } else {
                throw SQLiteException.New(r, r.ToString());
            }
        }

        public IEnumerable<T> ExecuteDeferredQuery<T>() where T : new()
        {
            return ExecuteDeferredQuery<T>(_conn.GetMapping(typeof(T)));
        }

        public List<T> ExecuteQuery<T>() where T : new()
        {
            return ExecuteDeferredQuery<T>(_conn.GetMapping(typeof(T))).ToList();
        }

        public List<T> ExecuteQuery<T>(TableMapping map)
        {
            return ExecuteDeferredQuery<T>(map).ToList();
        }

        public IEnumerable<T> ExecuteDeferredQuery<T>(TableMapping map)
        {
            if (_conn.Trace) {
#if DEBUG
                Console.WriteLine("Executing Query: " + this);
#endif
            }

            var stmt = Prepare();
            try {
                var cols = new TableMapping.Column[SQLite3.ColumnCount(stmt)];

                for (int i = 0; i < cols.Length; i++) {
                    var name = SQLite3.ColumnName16(stmt, i);
                    cols[i] = map.FindColumn(name);
                }

                while (SQLite3.Step(stmt) == SQLite3.Result.Row) {
                    var obj = Activator.CreateInstance(map.MappedType);
                    for (int i = 0; i < cols.Length; i++) {
                        if (cols[i] == null)
                            continue;
                        var colType = SQLite3.ColumnType(stmt, i);
                        var val = ReadCol(stmt, i, colType, cols[i].ColumnType);
                        cols[i].SetValue(obj, val);
                    }
                    yield return (T)obj;
                }
            } finally {
                SQLite3.Finalize(stmt);
            }
        }

        public T ExecuteScalar<T>()
        {
            if (_conn.Trace) {
#if DEBUG
                Console.WriteLine("Executing Query: " + this);
#endif
            }

            T val = default(T);

            var stmt = Prepare();
            if (SQLite3.Step(stmt) == SQLite3.Result.Row) {
                var colType = SQLite3.ColumnType(stmt, 0);
                val = (T)ReadCol(stmt, 0, colType, typeof(T));
            }
            Finalize(stmt);

            return val;
        }

        public void Bind(string name, object val)
        {
            _bindings.Add(new Binding {
                Name = name,
                Value = val
            });
        }

        public void Bind(object val)
        {
            Bind(null, val);
        }

        public override string ToString()
        {
            var parts = new string[1 + _bindings.Count];
            parts[0] = CommandText;
            var i = 1;
            foreach (var b in _bindings) {
                parts[i] = string.Format("  {0}: {1}", i - 1, b.Value);
                i++;
            }
            return string.Join(Environment.NewLine, parts);
        }

        Sqlite3Statement Prepare()
        {
            var stmt = SQLite3.Prepare2(_conn.Handle, CommandText);
            BindAll(stmt);
            return stmt;
        }

        void Finalize(Sqlite3Statement stmt)
        {
            SQLite3.Finalize(stmt);
        }

        void BindAll(Sqlite3Statement stmt)
        {
            int nextIdx = 1;
            foreach (var b in _bindings) {
                if (b.Name != null) {
                    b.Index = SQLite3.BindParameterIndex(stmt, b.Name);
                } else {
                    b.Index = nextIdx++;
                }
            }
            foreach (var b in _bindings) {
                BindParameter(stmt, b.Index, b.Value);
            }
        }

        internal static IntPtr NegativePointer = new IntPtr(-1);

        internal static void BindParameter(Sqlite3Statement stmt, int index, object value)
        {
            if (value == null) {
                SQLite3.BindNull(stmt, index);
            } else {
                if (value is Int32) {
                    SQLite3.BindInt(stmt, index, (int)value);
                } else if (value is String) {
                    SQLite3.BindText(stmt, index, (string)value, -1, NegativePointer);
                } else if (value is Byte || value is UInt16 || value is SByte || value is Int16) {
                    SQLite3.BindInt(stmt, index, Convert.ToInt32(value));
                } else if (value is Boolean) {
                    SQLite3.BindInt(stmt, index, (bool)value ? 1 : 0);
                } else if (value is UInt32 || value is Int64) {
                    SQLite3.BindInt64(stmt, index, Convert.ToInt64(value));
                } else if (value is Single || value is Double || value is Decimal) {
                    SQLite3.BindDouble(stmt, index, Convert.ToDouble(value));
                } else if (value is DateTime) {
                    SQLite3.BindText(stmt, index, ((DateTime)value).ToString("yyyy-MM-dd HH:mm:ss"), -1, NegativePointer);
                } else if (value.GetType().IsEnum) {
                    SQLite3.BindInt(stmt, index, Convert.ToInt32(value));
                } else if (value is byte[]) {
                    SQLite3.BindBlob(stmt, index, (byte[])value, ((byte[])value).Length, NegativePointer);
                } else {
                    throw new NotSupportedException("Cannot store type: " + value.GetType());
                }
            }
        }

        class Binding {
            public string Name { get; set; }

            public object Value { get; set; }

            public int Index { get; set; }
        }

        object ReadCol(Sqlite3Statement stmt, int index, SQLite3.ColType type, Type clrType)
        {
            if (type == SQLite3.ColType.Null) {
                return null;
            } else {
                if (clrType == typeof(String)) {
                    return SQLite3.ColumnString(stmt, index);
                } else if (clrType == typeof(Int32)) {
                    return (int)SQLite3.ColumnInt(stmt, index);
                } else if (clrType == typeof(Boolean)) {
                    return SQLite3.ColumnInt(stmt, index) == 1;
                } else if (clrType == typeof(double)) {
                    return SQLite3.ColumnDouble(stmt, index);
                } else if (clrType == typeof(float)) {
                    return (float)SQLite3.ColumnDouble(stmt, index);
                } else if (clrType == typeof(DateTime)) {
                    var text = SQLite3.ColumnString(stmt, index);
                    return DateTime.Parse(text);
                } else if (clrType.IsEnum) {
                    return SQLite3.ColumnInt(stmt, index);
                } else if (clrType == typeof(Int64)) {
                    return SQLite3.ColumnInt64(stmt, index);
                } else if (clrType == typeof(UInt32)) {
                    return (uint)SQLite3.ColumnInt64(stmt, index);
                } else if (clrType == typeof(decimal)) {
                    return (decimal)SQLite3.ColumnDouble(stmt, index);
                } else if (clrType == typeof(Byte)) {
                    return (byte)SQLite3.ColumnInt(stmt, index);
                } else if (clrType == typeof(UInt16)) {
                    return (ushort)SQLite3.ColumnInt(stmt, index);
                } else if (clrType == typeof(Int16)) {
                    return (short)SQLite3.ColumnInt(stmt, index);
                } else if (clrType == typeof(sbyte)) {
                    return (sbyte)SQLite3.ColumnInt(stmt, index);
                } else if (clrType == typeof(byte[])) {
                    return SQLite3.ColumnByteArray(stmt, index);
                } else {
                    throw new NotSupportedException("Don't know how to read " + clrType);
                }
            }
        }
    }

    /// <summary>
    /// Since the insert never changed, we only need to prepare once.
    /// </summary>
    public class PreparedSqlLiteInsertCommand : IDisposable {
        public bool Initialized { get; set; }

        protected SQLiteConnection Connection { get; set; }

        public string CommandText { get; set; }

        protected Sqlite3Statement Statement { get; set; }
#if USE_CSHARP_SQLITE
        internal static readonly Sqlite3Statement NullStatement = null;
#else
		internal static readonly Sqlite3Statement NullStatement = IntPtr.Zero;
#endif

        internal PreparedSqlLiteInsertCommand(SQLiteConnection conn)
        {
            Connection = conn;
        }

        public int ExecuteNonQuery(object[] source)
        {
            if (Connection.Trace) {
#if DEBUG
                Console.WriteLine("Executing: " + CommandText);
#endif
            }

            var r = SQLite3.Result.OK;

            if (!Initialized) {
                Statement = Prepare();
                Initialized = true;
            }

            //bind the values.
            if (source != null) {
                for (int i = 0; i < source.Length; i++) {
                    SQLiteCommand.BindParameter(Statement, i + 1, source[i]);
                }
            }
            r = SQLite3.Step(Statement);

            if (r == SQLite3.Result.Done) {
                int rowsAffected = SQLite3.Changes(Connection.Handle);
                SQLite3.Reset(Statement);
                return rowsAffected;
            } else if (r == SQLite3.Result.Error) {
                string msg = SQLite3.GetErrmsg(Connection.Handle);
                SQLite3.Reset(Statement);
                throw SQLiteException.New(r, msg);
            } else {
                SQLite3.Reset(Statement);
                throw SQLiteException.New(r, r.ToString());
            }
        }

        protected virtual Sqlite3Statement Prepare()
        {
            var stmt = SQLite3.Prepare2(Connection.Handle, CommandText);
            return stmt;
        }

        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        private void Dispose(bool disposing)
        {
            if (Statement != NullStatement) {
                try {
                    SQLite3.Finalize(Statement);
                } finally {
                    Statement = NullStatement;
                    Connection = null;
                }
            }
        }

        ~PreparedSqlLiteInsertCommand()
        {
            Dispose(false);
        }
    }

    public class TableQuery<T> : IEnumerable<T> where T : new() {
        public SQLiteConnection Connection { get; private set; }

        public TableMapping Table { get; private set; }

        Expression _where;
        List<Ordering> _orderBys;
        int? _limit;
        int? _offset;

        class Ordering {
            public string ColumnName { get; set; }

            public bool Ascending { get; set; }
        }

        TableQuery(SQLiteConnection conn, TableMapping table)
        {
            Connection = conn;
            Table = table;
        }

        public TableQuery(SQLiteConnection conn)
        {
            Connection = conn;
            Table = Connection.GetMapping(typeof(T));
        }

        public TableQuery<T> Clone()
        {
            var q = new TableQuery<T>(Connection, Table);
            q._where = _where;
            q._deferred = _deferred;
            if (_orderBys != null) {
                q._orderBys = new List<Ordering>(_orderBys);
            }
            q._limit = _limit;
            q._offset = _offset;
            return q;
        }

        public TableQuery<T> Where(Expression<Func<T, bool>> predExpr)
        {
            if (predExpr.NodeType == ExpressionType.Lambda) {
                var lambda = (LambdaExpression)predExpr;
                var pred = lambda.Body;
                var q = Clone();
                q.AddWhere(pred);
                return q;
            } else {
                throw new NotSupportedException("Must be a predicate");
            }
        }

        public TableQuery<T> Take(int n)
        {
            var q = Clone();
            q._limit = n;
            return q;
        }

        public TableQuery<T> Skip(int n)
        {
            var q = Clone();
            q._offset = n;
            return q;
        }

        bool _deferred = false;
        public TableQuery<T> Deferred()
        {
            var q = Clone();
            q._deferred = true;
            return q;
        }

        public TableQuery<T> OrderBy<U>(Expression<Func<T, U>> orderExpr)
        {
            return AddOrderBy<U>(orderExpr, true);
        }

        public TableQuery<T> OrderByDescending<U>(Expression<Func<T, U>> orderExpr)
        {
            return AddOrderBy<U>(orderExpr, false);
        }

        private TableQuery<T> AddOrderBy<U>(Expression<Func<T, U>> orderExpr, bool asc)
        {
            if (orderExpr.NodeType == ExpressionType.Lambda) {
                var lambda = (LambdaExpression)orderExpr;
                var mem = lambda.Body as MemberExpression;
                if (mem != null && (mem.Expression.NodeType == ExpressionType.Parameter)) {
                    var q = Clone();
                    if (q._orderBys == null) {
                        q._orderBys = new List<Ordering>();
                    }
                    q._orderBys.Add(new Ordering {
                        ColumnName = mem.Member.Name,
                        Ascending = asc
                    });
                    return q;
                } else {
                    throw new NotSupportedException("Order By does not support: " + orderExpr);
                }
            } else {
                throw new NotSupportedException("Must be a predicate");
            }
        }

        private void AddWhere(Expression pred)
        {
            if (_where == null) {
                _where = pred;
            } else {
                _where = Expression.AndAlso(_where, pred);
            }
        }

        private SQLiteCommand GenerateCommand(string selectionList)
        {
            var cmdText = "select " + selectionList + " from \"" + Table.TableName + "\"";
            var args = new List<object>();
            if (_where != null) {
                var w = CompileExpr(_where, args);
                cmdText += " where " + w.CommandText;
            }
            if ((_orderBys != null) && (_orderBys.Count > 0)) {
                var t = string.Join(", ", _orderBys.Select(o => "\"" + o.ColumnName + "\"" + (o.Ascending ? "" : " desc")).ToArray());
                cmdText += " order by " + t;
            }
            if (_limit.HasValue) {
                cmdText += " limit " + _limit.Value;
            }
            if (_offset.HasValue) {
                if (!_limit.HasValue) {
                    cmdText += " limit -1 ";
                }
                cmdText += " offset " + _offset.Value;
            }
            return Connection.CreateCommand(cmdText, args.ToArray());
        }

        class CompileResult {
            public string CommandText { get; set; }

            public object Value { get; set; }
        }

        private CompileResult CompileExpr(Expression expr, List<object> queryArgs)
        {
            if (expr == null) {
                throw new NotSupportedException("Expression is NULL");
            } else if (expr is BinaryExpression) {
                var bin = (BinaryExpression)expr;

                var leftr = CompileExpr(bin.Left, queryArgs);
                var rightr = CompileExpr(bin.Right, queryArgs);

                //If either side is a parameter and is null, then handle the other side specially (for "is null"/"is not null")
                string text;
                if (leftr.CommandText == "?" && leftr.Value == null)
                    text = CompileNullBinaryExpression(bin, rightr);
                else if (rightr.CommandText == "?" && rightr.Value == null)
                    text = CompileNullBinaryExpression(bin, leftr);
                else
                    text = "(" + leftr.CommandText + " " + GetSqlName(bin) + " " + rightr.CommandText + ")";
                return new CompileResult { CommandText = text };
            } else if (expr.NodeType == ExpressionType.Call) {

                var call = (MethodCallExpression)expr;
                var args = new CompileResult[call.Arguments.Count];

                for (var i = 0; i < args.Length; i++) {
                    args[i] = CompileExpr(call.Arguments[i], queryArgs);
                }

                var sqlCall = "";

                if (call.Method.Name == "Like" && args.Length == 2) {
                    sqlCall = "(" + args[0].CommandText + " like " + args[1].CommandText + ")";
                } else if (call.Method.Name == "Contains" && args.Length == 2) {
                    sqlCall = "(" + args[1].CommandText + " in " + args[0].CommandText + ")";
                } else {
                    sqlCall = call.Method.Name.ToLower() + "(" + string.Join(",", args.Select(a => a.CommandText).ToArray()) + ")";
                }
                return new CompileResult { CommandText = sqlCall };

            } else if (expr.NodeType == ExpressionType.Constant) {
                var c = (ConstantExpression)expr;
                queryArgs.Add(c.Value);
                return new CompileResult {
                    CommandText = "?",
                    Value = c.Value
                };
            } else if (expr.NodeType == ExpressionType.Convert) {
                var u = (UnaryExpression)expr;
                var ty = u.Type;
                var valr = CompileExpr(u.Operand, queryArgs);
                return new CompileResult {
                    CommandText = valr.CommandText,
                    Value = valr.Value != null ? Convert.ChangeType(valr.Value, ty, null) : null
                };
            } else if (expr.NodeType == ExpressionType.MemberAccess) {
                var mem = (MemberExpression)expr;

                if (mem.Expression.NodeType == ExpressionType.Parameter) {
                    //
                    // This is a column of our table, output just the column name
                    //
                    return new CompileResult { CommandText = "\"" + mem.Member.Name + "\"" };
                } else {
                    object obj = null;
                    if (mem.Expression != null) {
                        var r = CompileExpr(mem.Expression, queryArgs);
                        if (r.Value == null) {
                            throw new NotSupportedException("Member access failed to compile expression");
                        }
                        if (r.CommandText == "?") {
                            queryArgs.RemoveAt(queryArgs.Count - 1);
                        }
                        obj = r.Value;
                    }

                    //
                    // Get the member value
                    //
                    object val = null;

                    if (mem.Member.MemberType == MemberTypes.Property) {
                        var m = (PropertyInfo)mem.Member;
                        val = m.GetValue(obj, null);
                    } else if (mem.Member.MemberType == MemberTypes.Field) {
#if SILVERLIGHT
                        val = Expression.Lambda(expr).Compile().DynamicInvoke();
#else
						var m = (FieldInfo)mem.Member;
                        var eee = Expression.Lambda (expr);
						val = m.GetValue (obj);						
#endif
                    } else {
                        throw new NotSupportedException("MemberExpr: " + mem.Member.MemberType.ToString());
                    }

                    //
                    // Work special magic for enumerables
                    //
                    if (val != null && val is System.Collections.IEnumerable && !(val is string)) {
                        var sb = new System.Text.StringBuilder();
                        sb.Append("(");
                        var head = "";
                        foreach (var a in (System.Collections.IEnumerable)val) {
                            queryArgs.Add(a);
                            sb.Append(head);
                            sb.Append("?");
                            head = ",";
                        }
                        sb.Append(")");
                        return new CompileResult {
                            CommandText = sb.ToString(),
                            Value = val
                        };
                    } else {
                        queryArgs.Add(val);
                        return new CompileResult {
                            CommandText = "?",
                            Value = val
                        };
                    }
                }
            }
            throw new NotSupportedException("Cannot compile: " + expr.NodeType.ToString());
        }

        /// <summary>
        /// Compiles a BinaryExpression where one of the parameters is null.
        /// </summary>
        /// <param name="parameter">The non-null parameter</param>
        private string CompileNullBinaryExpression(BinaryExpression expression, CompileResult parameter)
        {
            if (expression.NodeType == ExpressionType.Equal)
                return "(" + parameter.CommandText + " is ?)";
            else if (expression.NodeType == ExpressionType.NotEqual)
                return "(" + parameter.CommandText + " is not ?)";
            else
                throw new NotSupportedException("Cannot compile Null-BinaryExpression with type " + expression.NodeType.ToString());
        }

        string GetSqlName(Expression expr)
        {
            var n = expr.NodeType;
            if (n == ExpressionType.GreaterThan)
                return ">";
            else if (n == ExpressionType.GreaterThanOrEqual) {
                return ">=";
            } else if (n == ExpressionType.LessThan) {
                return "<";
            } else if (n == ExpressionType.LessThanOrEqual) {
                return "<=";
            } else if (n == ExpressionType.And) {
                return "and";
            } else if (n == ExpressionType.AndAlso) {
                return "and";
            } else if (n == ExpressionType.Or) {
                return "or";
            } else if (n == ExpressionType.OrElse) {
                return "or";
            } else if (n == ExpressionType.Equal) {
                return "=";
            } else if (n == ExpressionType.NotEqual) {
                return "!=";
            } else {
                throw new System.NotSupportedException("Cannot get SQL for: " + n.ToString());
            }
        }

        public int Count()
        {
            return GenerateCommand("count(*)").ExecuteScalar<int>();
        }

        public IEnumerator<T> GetEnumerator()
        {
            if (!_deferred)
                return GenerateCommand("*").ExecuteQuery<T>().GetEnumerator();

            return GenerateCommand("*").ExecuteDeferredQuery<T>().GetEnumerator();
        }

        System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
        {
            return GetEnumerator();
        }
    }

    public static class SQLite3 {
        public enum Result : int {
            OK = 0,
            Error = 1,
            Internal = 2,
            Perm = 3,
            Abort = 4,
            Busy = 5,
            Locked = 6,
            NoMem = 7,
            ReadOnly = 8,
            Interrupt = 9,
            IOError = 10,
            Corrupt = 11,
            NotFound = 12,
            TooBig = 18,
            Constraint = 19,
            Row = 100,
            Done = 101
        }

        public enum ConfigOption : int {
            SingleThread = 1,
            MultiThread = 2,
            Serialized = 3
        }

#if !USE_CSHARP_SQLITE
		[DllImport("sqlite3", EntryPoint = "sqlite3_open")]
		public static extern Result Open (string filename, out IntPtr db);

		[DllImport("sqlite3", EntryPoint = "sqlite3_close")]
		public static extern Result Close (IntPtr db);

		[DllImport("sqlite3", EntryPoint = "sqlite3_config")]
		public static extern Result Config (ConfigOption option);

		[DllImport("sqlite3", EntryPoint = "sqlite3_busy_timeout")]
		public static extern Result BusyTimeout (IntPtr db, int milliseconds);

		[DllImport("sqlite3", EntryPoint = "sqlite3_changes")]
		public static extern int Changes (IntPtr db);

		[DllImport("sqlite3", EntryPoint = "sqlite3_prepare_v2")]
		public static extern Result Prepare2 (IntPtr db, string sql, int numBytes, out IntPtr stmt, IntPtr pzTail);

		public static IntPtr Prepare2 (IntPtr db, string query)
		{
			IntPtr stmt;
			var r = Prepare2 (db, query, query.Length, out stmt, IntPtr.Zero);
			if (r != Result.OK) {
				throw SQLiteException.New (r, GetErrmsg (db));
			}
			return stmt;
		}

		[DllImport("sqlite3", EntryPoint = "sqlite3_step")]
		public static extern Result Step (IntPtr stmt);

		[DllImport("sqlite3", EntryPoint = "sqlite3_reset")]
		public static extern Result Reset (IntPtr stmt);

		[DllImport("sqlite3", EntryPoint = "sqlite3_finalize")]
		public static extern Result Finalize (IntPtr stmt);

		[DllImport("sqlite3", EntryPoint = "sqlite3_last_insert_rowid")]
		public static extern long LastInsertRowid (IntPtr db);

		[DllImport("sqlite3", EntryPoint = "sqlite3_errmsg16")]
		public static extern IntPtr Errmsg (IntPtr db);

		public static string GetErrmsg (IntPtr db)
		{
			return Marshal.PtrToStringUni (Errmsg (db));
		}

		[DllImport("sqlite3", EntryPoint = "sqlite3_bind_parameter_index")]
		public static extern int BindParameterIndex (IntPtr stmt, string name);

		[DllImport("sqlite3", EntryPoint = "sqlite3_bind_null")]
		public static extern int BindNull (IntPtr stmt, int index);

		[DllImport("sqlite3", EntryPoint = "sqlite3_bind_int")]
		public static extern int BindInt (IntPtr stmt, int index, int val);

		[DllImport("sqlite3", EntryPoint = "sqlite3_bind_int64")]
		public static extern int BindInt64 (IntPtr stmt, int index, long val);

		[DllImport("sqlite3", EntryPoint = "sqlite3_bind_double")]
		public static extern int BindDouble (IntPtr stmt, int index, double val);

		[DllImport("sqlite3", EntryPoint = "sqlite3_bind_text")]
		public static extern int BindText (IntPtr stmt, int index, string val, int n, IntPtr free);

		[DllImport("sqlite3", EntryPoint = "sqlite3_bind_blob")]
		public static extern int BindBlob (IntPtr stmt, int index, byte[] val, int n, IntPtr free);

		[DllImport("sqlite3", EntryPoint = "sqlite3_column_count")]
		public static extern int ColumnCount (IntPtr stmt);

		[DllImport("sqlite3", EntryPoint = "sqlite3_column_name")]
		public static extern IntPtr ColumnName (IntPtr stmt, int index);

		[DllImport("sqlite3", EntryPoint = "sqlite3_column_name16")]
		private static extern IntPtr ColumnName16Internal (IntPtr stmt, int index);
		public static string ColumnName16(IntPtr stmt, int index)
		{
			return Marshal.PtrToStringUni(ColumnName16Internal(stmt, index));
		}

		[DllImport("sqlite3", EntryPoint = "sqlite3_column_type")]
		public static extern ColType ColumnType (IntPtr stmt, int index);

		[DllImport("sqlite3", EntryPoint = "sqlite3_column_int")]
		public static extern int ColumnInt (IntPtr stmt, int index);

		[DllImport("sqlite3", EntryPoint = "sqlite3_column_int64")]
		public static extern long ColumnInt64 (IntPtr stmt, int index);

		[DllImport("sqlite3", EntryPoint = "sqlite3_column_double")]
		public static extern double ColumnDouble (IntPtr stmt, int index);

		[DllImport("sqlite3", EntryPoint = "sqlite3_column_text")]
		public static extern IntPtr ColumnText (IntPtr stmt, int index);

		[DllImport("sqlite3", EntryPoint = "sqlite3_column_text16")]
		public static extern IntPtr ColumnText16 (IntPtr stmt, int index);

		[DllImport("sqlite3", EntryPoint = "sqlite3_column_blob")]
		public static extern IntPtr ColumnBlob (IntPtr stmt, int index);

		[DllImport("sqlite3", EntryPoint = "sqlite3_column_bytes")]
		public static extern int ColumnBytes (IntPtr stmt, int index);

		public static string ColumnString (IntPtr stmt, int index)
		{
			return Marshal.PtrToStringUni (SQLite3.ColumnText16 (stmt, index));
		}

		public static byte[] ColumnByteArray (IntPtr stmt, int index)
		{
			int length = ColumnBytes (stmt, index);
			byte[] result = new byte[length];
			if (length > 0)
				Marshal.Copy (ColumnBlob (stmt, index), result, 0, length);
			return result;
		}
#else
        public static Result Open(string filename, out Sqlite3.sqlite3 db)
        {
            db = new Sqlite3.sqlite3();
            return (Result)Sqlite3.sqlite3_open(filename, ref db);
        }

        public static Result Close(Sqlite3.sqlite3 db)
        {
            return (Result)Sqlite3.sqlite3_close(db);
        }

        public static Result BusyTimeout(Sqlite3.sqlite3 db, int milliseconds)
        {
            return (Result)Sqlite3.sqlite3_busy_timeout(db, milliseconds);
        }

        public static int Changes(Sqlite3.sqlite3 db)
        {
            return Sqlite3.sqlite3_changes(db);
        }

        public static Sqlite3.Vdbe Prepare2(Sqlite3.sqlite3 db, string query)
        {
            Sqlite3.Vdbe stmt = new Sqlite3.Vdbe();
            var r = Sqlite3.sqlite3_prepare_v2(db, query, query.Length, ref stmt, 0);
            if (r != 0) {
                throw SQLiteException.New((Result)r, GetErrmsg(db));
            }
            return stmt;
        }

        public static Result Step(Sqlite3.Vdbe stmt)
        {
            return (Result)Sqlite3.sqlite3_step(stmt);
        }

        public static Result Reset(Sqlite3.Vdbe stmt)
        {
            return (Result)Sqlite3.sqlite3_reset(stmt);
        }

        public static Result Finalize(Sqlite3.Vdbe stmt)
        {
            return (Result)Sqlite3.sqlite3_finalize(ref stmt);
        }

        public static long LastInsertRowid(Sqlite3.sqlite3 db)
        {
            return Sqlite3.sqlite3_last_insert_rowid(db);
        }

        public static string GetErrmsg(Sqlite3.sqlite3 db)
        {
            return Sqlite3.sqlite3_errmsg(db);
        }

        public static int BindParameterIndex(Sqlite3.Vdbe stmt, string name)
        {
            return Sqlite3.sqlite3_bind_parameter_index(stmt, name);
        }

        public static int BindNull(Sqlite3.Vdbe stmt, int index)
        {
            return Sqlite3.sqlite3_bind_null(stmt, index);
        }

        public static int BindInt(Sqlite3.Vdbe stmt, int index, int val)
        {
            return Sqlite3.sqlite3_bind_int(stmt, index, val);
        }

        public static int BindInt64(Sqlite3.Vdbe stmt, int index, long val)
        {
            return Sqlite3.sqlite3_bind_int64(stmt, index, val);
        }

        public static int BindDouble(Sqlite3.Vdbe stmt, int index, double val)
        {
            return Sqlite3.sqlite3_bind_double(stmt, index, val);
        }

        public static int BindText(Sqlite3.Vdbe stmt, int index, string val, int n, IntPtr free)
        {
            return Sqlite3.sqlite3_bind_text(stmt, index, val, n, null);
        }

        public static int BindBlob(Sqlite3.Vdbe stmt, int index, byte[] val, int n, IntPtr free)
        {
            return Sqlite3.sqlite3_bind_blob(stmt, index, val, n, null);
        }

        public static int ColumnCount(Sqlite3.Vdbe stmt)
        {
            return Sqlite3.sqlite3_column_count(stmt);
        }

        public static string ColumnName(Sqlite3.Vdbe stmt, int index)
        {
            return Sqlite3.sqlite3_column_name(stmt, index);
        }

        public static string ColumnName16(Sqlite3.Vdbe stmt, int index)
        {
            return Sqlite3.sqlite3_column_name(stmt, index);
        }

        public static ColType ColumnType(Sqlite3.Vdbe stmt, int index)
        {
            return (ColType)Sqlite3.sqlite3_column_type(stmt, index);
        }

        public static int ColumnInt(Sqlite3.Vdbe stmt, int index)
        {
            return Sqlite3.sqlite3_column_int(stmt, index);
        }

        public static long ColumnInt64(Sqlite3.Vdbe stmt, int index)
        {
            return Sqlite3.sqlite3_column_int64(stmt, index);
        }

        public static double ColumnDouble(Sqlite3.Vdbe stmt, int index)
        {
            return Sqlite3.sqlite3_column_double(stmt, index);
        }

        public static string ColumnText(Sqlite3.Vdbe stmt, int index)
        {
            return Sqlite3.sqlite3_column_text(stmt, index);
        }

        public static string ColumnText16(Sqlite3.Vdbe stmt, int index)
        {
            return Sqlite3.sqlite3_column_text(stmt, index);
        }

        public static byte[] ColumnBlob(Sqlite3.Vdbe stmt, int index)
        {
            return Sqlite3.sqlite3_column_blob(stmt, index);
        }

        public static int ColumnBytes(Sqlite3.Vdbe stmt, int index)
        {
            return Sqlite3.sqlite3_column_bytes(stmt, index);
        }

        public static string ColumnString(Sqlite3.Vdbe stmt, int index)
        {
            return Sqlite3.sqlite3_column_text(stmt, index);
        }

        public static byte[] ColumnByteArray(Sqlite3.Vdbe stmt, int index)
        {
            return ColumnBlob(stmt, index);
        }
#endif

        public enum ColType : int {
            Integer = 1,
            Float = 2,
            Text = 3,
            Blob = 4,
            Null = 5
        }
    }

}

